title: Clubs volunteering for sports injury prevention research - is there any selection bias?
mesh_terms: D001265:Athletic Injuries / Q000517:prevention & control; D005538:Football / Q000293:injuries*; D006260:Head Protective Devices; D006801:Humans; D009064:Mouth Protectors; D018579:Patient Selection; D016032:Randomized Controlled Trials as Topic; D015983:Selection Bias; D014739:Victoria